[turbofan] The BytecodeGraphBuilder should never insert the empty frame state.

It's always possible to deoptimize to Ignition from TurboFan, and we
don't use Ignition for asm.js code, so there's no need to have the empty
frame state magic in the BytecodeGraphBuilder.

R=mstarzinger@chromium.org
BUG=v8:4280

Review-Url: https://codereview.chromium.org/2008243002
Cr-Commit-Position: refs/heads/master@{#36505}

src/compiler/bytecode-graph-builder.cc

@@ -355,9 +355,6 @@ void BytecodeGraphBuilder::Environment::PrepareForLoop() {
 
 bool BytecodeGraphBuilder::Environment::StateValuesRequireUpdate(
     Node** state_values, int offset, int count) {
-  if (!builder()->deoptimization_enabled_) {
-    return false;
-  }
   if (*state_values == nullptr) {
     return true;
   }
@@ -385,10 +382,6 @@ void BytecodeGraphBuilder::Environment::UpdateStateValues(Node** state_values,
 
 Node* BytecodeGraphBuilder::Environment::Checkpoint(
     BailoutId bailout_id, OutputFrameStateCombine combine) {
-  if (!builder()->deoptimization_enabled_) {
-    return builder()->jsgraph()->EmptyFrameState();
-  }
-
   // TODO(rmcilroy): Consider using StateValuesCache for some state values.
   UpdateStateValues(&parameters_state_values_, 0, parameter_count());
   UpdateStateValues(&registers_state_values_, register_base(),
@@ -423,7 +416,6 @@ bool BytecodeGraphBuilder::Environment::StateValuesAreUpToDate(
 
 bool BytecodeGraphBuilder::Environment::StateValuesAreUpToDate(
     int output_poke_offset, int output_poke_count) {
-  if (!builder()->deoptimization_enabled_) return true;
   // Poke offset is relative to the top of the stack (i.e., the accumulator).
   int output_poke_start = accumulator_base() - output_poke_offset;
   int output_poke_end = output_poke_start + output_poke_count;
@@ -449,7 +441,6 @@ BytecodeGraphBuilder::BytecodeGraphBuilder(Zone* local_zone,
           FrameStateType::kInterpretedFunction,
           bytecode_array()->parameter_count(),
           bytecode_array()->register_count(), info->shared_info())),
-      deoptimization_enabled_(info->is_deoptimization_enabled()),
       merge_environments_(local_zone),
       exception_handlers_(local_zone),
       current_exception_handler_(0),

src/compiler/bytecode-graph-builder.h

@@ -218,10 +218,6 @@ class BytecodeGraphBuilder {
   const BytecodeBranchAnalysis* branch_analysis_;
   Environment* environment_;
 
-  // Indicates whether deoptimization support is enabled for this compilation
-  // and whether valid frame states need to be attached to deoptimizing nodes.
-  bool deoptimization_enabled_;
-
   // Merge environments are snapshots of the environment at points where the
   // control flow merges. This models a forward data flow propagation of all
   // values from all predecessors of the merge in question.